The field of art to which this invention pertains is topical sun or radiation screening or tanning preparations.
Although the potentially damaging effects of sunlight on human skin have been well publicized, many people have occupations which require them to be exposed to the sun for long periods of time. Many others choose to spend their leisure time outdoors playing tennis or golf, swimming, fishing, skiing, or sunbathing. To protect human skin against erythema-causing radiation from the sun, a variety of sunscreening compositions have been developed which contain compounds which absorb ultraviolet light in the erythemal region.
Commercially available sun screen and sun block formulations provide excellent protection against severe sun burning of exposed skin for extended periods so long as they remain on exposed areas and are not washed off when contacted with water or perspiration. Unfortunately, bathing in pool water or ocean water will usually result in most conventional sun screen and sun block formulations being washed away from the skin thereby leaving exposed areas of skin.
In U.S. Pat. No. 4,781,914, sun screen compositions which are also moisturizer compositions are described. Such compositions are made in the form of a sprayable oil-in-water emulsion which when applied to the skin and rubbed in inverts to a water-in-oil creamy nongreasy film.
Water resistant sunscreen compositions which contain a water insoluble acrylate polymer are described in U.S. Pat. No. 4,172,122.
Substantive PABA (para-aminobenzoic acid) formulations which contain water soluble cellulosics are disclosed in U.S. Pat. No. 4,254,102.
Water-proof sunscreen compositions which contain ethyl hydroxyethyl cellulose polymers are described in U.S. Pat. No. 4,671,955.
In U.S. Pat. No. 4,559,225, water-proof sunscreen compositions which contain a cellulose polymer, a solvent, an ultra-violet sunscreening agent, and an emollient are disclosed.
Cosmetic manufacturers are constantly striving to improve personal skin care products, which not only offer protection from the sun, but also contribute to the smoothing and softening of the skin.